Transportation of solids



March 1954 s. A. JONES ET AL TRANSPORTATION OF SOLIDS Filed Jan. 15,1952 2 Sheets-Sheet l INVENTORS SAM A. JONES ERIC H. REICHL Haz NEY

March 16, 1954 s. A. JONES ETAL TRANSPORTATION OF SOLIDS 2 Sheets-Sheet2 Filed Jan. 15, 1952 m aw Mm R00 Y o E T E F N N R R E 0 V H. T M A ASm j.

WW E. ..i:....% J 11 mm embodiment of .a siurryipumpingsrauon to whichPatented Mar. 16, 1954 NITED STATE PAT T O I TRANSPORTATION OF SOLIDSsylvania Application January 15, 1952, Serial No. 266,569 7 Claims. (01.302 14) The present invention relates .to the art of transporting solidssuspended in a liquid vehicle.

This application is a continuation-impart of our copending patentapplication S. N. 204,623, filed January 5, 1951, and entitledTransportation of Solids Through Pipelines.

Conventional mechanical pumps in general are unsatisfactory for pumpingsolids which are suspended in liquids because of the excessive wearingof the moving parts oizsuch pumps occasioned by the solids and alsobecause of the attrition of the solids occasioned .by the moving parts01 the pump. The present :inyehtion'is directed to a pumping devicewhich is capable of raising the pressure Ofsolidliqu-idlsuspensionswithout permitting the solids to contact themoving parts of the pumping equipment. For convenience, we shallhereafter refer to the.suspensions of solids in liquids as slurries. Q

According to this invention, equal volumes of the slurry, hereinaftercalledFslu-gs, tare introduced alternately into one :of two paralleltransfer zones, are pressurized thereinlby :means of a high pressurepumping fluid, and :are discharged therefrom at an elevated pressure.:Pumping fluid is continuously.recoveredtrom theitransier zones, isrepressurized, and recirculatedto :raise the pressure of other.slu'gslof slurry.

We have discovered that the operation .of such a pumping system isgreatly improved by the introduction of a small portion of :the pumpingliquid between successive slugs of apressurized slurry. This addition ofpumping liquid assures that the slurry is completely removed :from eachpumping stroke. To compensate for the loss .of

the small portion of pumping iliquididuring .eao'h pumping stroke, asmall amount of make-up pumping liquid must be addedlto the :pumpingsystem.

The object of this invention is tOsPTOVidE'fOI pumping slurries withoutcausing excessive wear or attrition" on themoving parts of the-pumping:system or on the itransportedzsolids.

Another object of. the invention is .zto provide a system for:elevatinglthe ipressureiof *a slurry in a simple manner.

For a further understanding :of nur invention, its additional objectsand advantages, reference should be had to theaccompany n :descriptionand drawings in which:

Figure 1 is a drawing, .partly diagrammatic and partly incrosssection,showingthepreferred thepresen't inventionlis applicablejahd Figure 2shows the apparatus of Figure 1 in a "different "stage of operation;"and communicatewit-h a transfer pipe 36.

Figure 3 is a drawing, partly diagrammatic and partly in cross section,showing another embodiment of pumping station to which the presentinvention is applicable; and

Figure 4 shows the apparatus of Figure 3 in a difierent stage ofoperation.

Figures 1 and 2 represent pumping apparatus corresponding to thatdisclosed in a U. S. patent application Serial No. 266,568 filed on evendate herewith, by one of the present inventors and entitledTransportation of Solids Through Pipelines, and assigned :to theassignee of the present application.

Figures 3 and ,4 represent pumping apparatus corresponding to thatdisclosed in U. S. patent application S. N. 204,628, filed January 15,1951, referred to above.

Referring to Figure 1, a pumping apparatus for pumping a suspension offinely divided coal in water is shown in combination with azslurrytransportation pipeline proper which ,has a low pressure section and ahigh pressure section 3|. Communicating with the low pressure section 36are two conduits .33 and 34 whose diameter is substantially the same asthat of the pipeline proper. Communicating with the high pressurepipeline section are two conduitst'l and 38. Conduits 33 and 31 join andcommunicate with a transfer ,pipe 35,; conduits 34 and38 join and Thetransfer pipes 35 and 36 ,are of equal length .and have a diametersubstantially the same as that of the pipeline proper.

Check valves 39,, 40., 4| and 42 are provided in the conduits 33, .34,.31 .and 38 respectively. The check valves 39 and 40 permitfluids toflow only away from the low pressure pipeline section 30 the checkvalves 41 and 42 permit fluids to flow only toward the "high pressurepipeline section 3|. The extended terminals of the transfer pipes35-and3-6 join atthe diametrically opposite apertures ofaiour-waywalvefi which is adapted for cyclic operation.

A continuously operating high "pressure water pump "46 drawssuction fromai low pressure water pipe 44 and discharges :high pressure waterthrough high pressure pipe .45. 'IThe high pressure water line 45 andthe low pressure water .line 44 communicate gwithgthe remainin .01

for introducing the make-up "water and a valve 3 49 is provided tothrottle the make-up water according to the operating conditionsexisting in the system.

The operation of the pumping system shown in Figures 1 and 2 will bebriefly described. For further details relating to this pumping scheme,reference should be had to the above mentioned copending U. S. patentapplication filed on even date herewith.

A slurry of the finely divided coal and water travels at constantvelocity through pipeline section 30 under a low pressure. The four-wayvalve 43 has been in theposition indicated in Figure 1 for almost onecomplete half-cycle of the pumping apparatus. Throughout this halfcycle,low pressure slurry from the pipeline as has been passing throughconduit 33, open check valve 39 and into the transfer pipe 35. As shown,the slug of slurry 50 has filled the transfer pipe 35 to a point nearthe four-way valve 33. The slurry which has been filling the transferpipe 35 has been displacing water from the transfer pipe 35 through thefour-way valve 43 into the low pressure water line 44. The pump it hasbeen repressurizing the Water from pipe ill and discharging said waterunder high pressure through the high pressure water line .5 and thefour-way valve 43 into the transfer pipe 36. The slug of slurry 5|,which had been introduced into the transfer pipe 36 during the precedinghalf-cycie of the pumping system, has been displaced by the highpressure water and is discharged under high pressure from the transferpipe 35 through the conduit 38 and open check valve 2 into the highpressure pipeline section 3i for further transportation.

During the entire half-cycle shown in Figure l, the pressure in transferpipe 36 exceeds that in the low pressure slurry pipeline section 55 and3|. Consequently, the check valve GE is closed and the check valve 42 isopen throughout the half-cycle. Similarly the pressure in transfer pipe35, during the entire half-cycle shown in Figure 1, is less than that inthe slurry pipeline 30 and 3!. Accordingly, the check valve 5i is closedand the check valve 39 is open throughout the half-cycle.

At the termination of the pumping stroke illustrated by Figure l, theslurry slug 5i} will have advanced in the transfer pipe 35 to a pointjust short of the four-way valve 43. At this same moment, all of theslurry slug 5i will have been displaced from the transfer pipe 36 pastthe check valve 42 in the conduit 38 and, in addition, a small slug ofclean pressurized water will have followed the slug of slurry 5i throughthe check valve 38. Thereupon the system will be in condition forswitching the four-way valve 43 to the position shown in Figure 2 inorder that the other half-cycle may commence. The switching of valve 43may be eifected by any conventional timing deviceinot shown).

The apparatus of Figure 2 is identical with that shown in Figure 1except that (a) the valve 43 is in its alternate position, where itremains throughout the half-cycle illustrated by Figure 2, and (b) thecheck valves are in their alternate position automatically to correspondto the reversed position of the valve 43. As shown in Figure 2, highpressure water enters the transfer pipe 35 from the high pressure waterline 45. Water which has been introduced into the transfer pipe 36during the preceding half-cycle (Figure 1) is withdrawn through thevalve 43 to the low pressure water line 44 for repressurizing andrecirculation into transfer pipe 35.

Check valves 39 and 42 are closed; check valves it and 4! are open.Slurry from the low pressure pipeline 39 enters the transfer pipe 36through conduit 34 and the open check valve iii. Pressurized slurry fromtransfer pipe 35 is displaced under high pressure through conduit 3i andopen check valve ti into the high pressure slurry pipeline 3|. Theoperation continues until the slug of slurry 52 fills the transfer pipe36 to a point just short of the four-way valve 43. This pointcorresponds to the point of furthest advance of the slurry slug in theother transfer pipe during the preceding half-cycle.

t this precise moment, all of the slurry slug 5! has been dischargedfrom the transfer ipe 35 and a small slug of clear water has followedthe slug of slurry through the check valve 4|. The valve 413 then is incondition for switching back to the position illustrated in Figure l.The first half-cycle thereupon is repeated.

Throughout both half-cycles of the pumping system, clear make-up wateris continuously added to the low pressure water pipe G l through conduitll to compensate for the small amount of water which is discharged intothe pipeline proper following each pumping stroke.

We have found that the addition of a small slug of clear water to thepipline proper between each slug of slurry increases the useful life ofthe check valves All and 42 by permitting them to be actuated only inclear water. Furthermore, we have found that the controlled use of waterslugs prevents the slurry from entering the four-way valve 43. This notonly means that the four-way valve thus operates only in clear water andthereby has a maximum useful life, but also slurry is prevented fromentering the water pump 45 where any solids could cause great damage torapidly moving parts of the pump. Unless the small slug of clear wateris employed after each slug of slurry is discharged, each successiveslurry slug will approach a point in the transfer pipe nearer to thefour-way valve 43 than the preceding slug. After a few pumping cycles,the slurry will creep into the valve and thence into the water pumpingsystem. Water slugs and make-up water in accordance with the presentinvention, prevent this creeping phenomenon.

The method of the present invention will now be described in connectionwith the apparatus illustrated in Figures 3 and 4. The operation of thisapparatus will be briefly described. For further operational details,reference should be had to the above mentioned copending U. S. patentapplication S. N. 204,628, filed January 5, 1951.

The pumping apparatus is shown in combination with a pipeline which hasa low pressure section 69 and a high pressure section 6!. Two four-wayvalves are provided: the low pressure pipeline section communicates withone valve aperture of one valve 62 and the high pressure pipelinesection communicates with one aperture of the other valve 53. A highpressure water pump 64 is provided for elevating the pressure of waterfrom low pressure water line 65 and discharging said water underpressure through high pressure Water line 86. The high pressure waterline communicates with an aperture of the four-way valve 62 oppositefrom that of the low pressure pipeline 60. The low pressure water line65 communicates with an aperture of the reunway valve 63 opposite fromthat or the high pressure pipeline 6 I Two transfer pipes 61 and 68 areprovided with a diameter substantially the .sameas that of the pipelineproper. These transfer pipes are of the same length and communicate atone end with the two remaining valve apertures or the fourway valve 62-.At their other ends, these transfer pipes communicate with the tworemaining apertures of the four-way valve 63. A cycle timing device 69is provided to actuate simultaneously the two four-way valves 62 and '63at regular predetermined time intervals.

With the valves in the position shown in Figure 3, slurry from the lowpressure section of the pipeline 6 enters the transfer pipe :61 throughthe valve 62. Water from the transfer pipe e1 passes through the valve63 into the low pressure water line 65. The pump 64 draws its suctionfrom the water pipe 65, pressurizes the water and discharges it into thehigh pressure water line 69. High pressure water passes through thefourway valve 62 into the transfer pipe 68 where it displaces apreviously introduced slug of slurry into the pipeline proper 6| throughthe valve 63. The half-cycle as illustrated in Figure 3 is almostterminated. The slug of slurry ll! being introduced into the transferpipe 61 has 'almost reached the four-way valve 63. Similarly the slug ofslurry "H, which was introduced into the transfer pipe 68 during thepreceding half-cycle, has been almost fully discharged from the transferpipe. The valves "62 and 63 will be actuated simultaneously when theslug of slurry 10 reaches a predetermined point in the transfer pipe 61,just short of the valve '63. At this same moment, the entire slugofslurry 'il will have passed through the valve 63 and also a small amountof additional clear water will have followed the slug of slurry throughthe valve 553. When the valves are switched accordingly, they willassume the positions shown in Figure 4. Thus, Figure 4 illustrates theconditions prevailing throughout the other half-cycle of the pumpingsystem. The slurry is shown at a point about midway through the secondhalfcycle.

During the half-cycle of Figure 4, slurry from pipeline 6B is introducedinto the transfer pipe 68 through the four-way valve 62. Water from thetransfer pipe 68 passes through the four-way valve 63 into the lowpressure water line 65 to the pump 64 where it is pressurized anddischarged into the high pressure water line 66. The high pressure waterpasses through the fourway valve 62 into the transfer pipe 61 where itpressurizes the slug of slurry therein. The slug of slurry I isdischarged under pressure into the pipeline proper 6|. The half-cycle ofFigure 4 continues until the newly introduced slug of slurry H reaches apoint just short of the fourway valve 63. At the same moment, the entireslug of slurry it! has passed through the valve 63 and has been followedby a small slug of clear water. Thereupon the valves are switched backto the position shown in Figure 3 and the first half-cycle is repeated.

To compensate the recirculating water system for the small slugs ofwater which are discharged following each slug of slurry, a make-upwater system is provided. Clear make-up water is introduced from conduit12 into the low pressure water line 65 continuously under the control ofa valve 13. A pump 14 is provided in conduit 12 to furnish the necessarypressure. 7

The valve switching o eration in this moiiiih cationof the pumpingapparatus is accomplished by means of some form of automatic timing de'vice es which is regulated to actuate the valve switching mechanism atregular predetermined time intervals. The predetermined time is thattime required for-a slug of slurry to substantially fill one of thetransfer pipes as above described. This time, of course, is a functionof the linear velocity of the slurry in the pipeline proper.

Also in the pumping apparatus of Figures 3 and 4, we have discoveredthat the addition of a small slug of clear water to the dischargepipeline is necessary in order to assure that the four-way valve 63operates only in clear water, thereby reducing the attrition of thevalve parts from the solids in the slurry. Moreover, unless a small slugof clear water is employed following each slug of slurry, some solidparticles will remain in the transfer pipes after the four-way valveshave been switched. These solids thereupon would be directed into thelow pressure water line 65 and thence into the pump 64, thereby reducingthe useful life of the pump. However, if the entire transfer pipe andvalve 63 are flushed out by means of an additional small slug of clearwater in accordance with the present invention, these difficulties areavoided.

The two pumping systems described herein for transporting slurriesinclude the common steps of removing equal slugs of slurry from apipeline, transferring these slugs to a transfer zone, pressurizing theslugs of slurry by means of a high pressure liquid, displacing the slugsof slurry back into the pipeline by means of the high pressure liquid,introducing small slugs of the clear liquid'into the pipeline followingeach slug of slurry, recovering the pumping liquid, repressu-rizing thepumping liquid and recycling the pumping liquid for further use as apressurizing medium. In order to compensate for the introduction ofsmall amounts of clear liquid into the discharge pipeline after eachslurry slug, it is necessary that the supply of pumping water-beaugmented by furnishing clear make-up liquid into the system through thelow pressure portion or the recirculating liquid pumping system.

Although the present specification presents only two modifications ofpumping systems to which the present invention is applicable,nevertheless it is comprehended that the present invention be applied toany system for pumping solids in a liquid vehicle in which the pumpingimpetus is supplied by means of an independent recirculating liquidmedium. For example, the two copending patent applications referred toabove disclose various modifications of pumping schemes to which thepresent invention is applicable.

It should be pointed out that the pumping systems of the above mentionedtwo copending applications are limited to systems in which the transferzones are of substantially the same diameter as the pipeline proper. Thepurpose of this limitation is to maintain a substantially constantvelocity of the slurries through the transfer zones to minimize thesettling tendencies of the solids. However, the present invention iscomprehended in a broader form and is applicable even to systems inwhich the solids settling tendency is not a factor. Thus, the presentinvention is intended to pertain to recirculating liquid pumping systemsin which the transfer zones have diameters which differ from that of thepipeline proper. For example, the transfer zones 7 could be tanks. Itshould also be emphasized that the pumping fluid need not be the sameliquid as that used in the slurry.

According to the provisions of the patent statutes, we have explainedthe principle, preferred embodiment and mode of operation of ourinvention and have illustrated and described what we now consider torepresent its best embodiment. However, we desire to have it understoodthat, within the scope of the appended claims, the invention may bepracticed otherwise than as specifically illustrated and described.

We claim:

1. In a method for pumping slurries in a pumping system which employs arecirculating pumping liquid to pressurize slugs of slurry, theimprovement which comprises the steps of discharging a slug of thepumping liquid directly following each slug of discharged slurry andadding make-up pumping liquid to the recirculating pumping liquid systemto compensate for the slugs of pumping liquid which are discharged.

2. A method for pumping slurries through pipes which comprisesintroducing equal volume slugs of slurry alternately into one of twotransfer zones connected in parallel, introducing pressurized pumpingliquid into said transfer zone to pressurize said slurry in saidtransfer zone, discharging said slurry under pressure into a pipeline bydisplacement with said pumping liquid, adding a slug of said pumpingliquid to said pipeline directly following the discharge of said slug ofslurry into the said pipeline, recovering the remaining pumping liquid,adding make-up pumping liquid to said recovered pumping liquid,repressurizing said pumping liquid and recirculating the repressurizedpumping liquid to one of 'the said transfer zones.

3. A method for continuously pumping slurries through a pipeline whichcomprises introducing a slug of slurry into a low pressure transfer zoneof two transfer zones connected in parallel, said transfer zones beingadapted to function alternately as low pressure zones and high pressurezones, concurrently recovering previously introduced pumping liquid fromsaid low pressure "transfer zone, continuously adding make-up pumpingliquid to said recovered pumping liquid, continuously pressurizing saidpumping liquid and introducing said pressurized pumping liquid into saidhigh pressure transfer zone to displace therefrom a slug of slurry whichhas been previously introduced therein, discharging from said highpressure transfer zone in addition to said previously introduced slug ofslurry a slug of said pressurized pumping liquid, thereupon diverting anext slug of slurry into the transfer zone containing pumping liquid anddiverting said high pressure pumping liquid to the transfer zonecontaining a slug of slurry to repeat the pumping stroke in a cyclicmanner.

4. The method of claim 3 in which the slurry and also the pumping liquidpass unidirectionally and sequentially through said transfer zones.

5. The method of claim 3 in which the slurry is introduced into saidtransfer zones in one direction and is discharged from said transferzones in the reverse direction.

6. The method of claim 3 in which the slurry is a mixture of coal andwater and the pumping liquid is water.

'7. The method of transporting solids through a pipeline which comprisessuspending the solids in a subdivided form in a liquid, introducing theresulting suspension into a pipeline, substantially continuously formingdiscrete slugs of said suspension of predetermined and equal volume,pressurizing each of said slugs by means of a hydraulic liquid,discharging said pressurized slugs and thereafter a portion of saidhydraulic liquid, recombining said pressurized slugs and said portionsof hydraulic liquid in a continuous sequential stream, and supplyingfresh hydraulic fluid in an amout corresponding to that discharged.

SAM A. JONES. ERIC H. REICHL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 599,658 Lempert Feb. 22, 1898 2,471,498 Rood May 31, 19492,553,276 Reed May 15, 1951

